eth_newPendingTransactionFilter

eth_newPendingTransactionFilter creates a server-side filter on the Avalanche C-Chain (chain ID 43114, gas paid in AVAX) that captures transactions entering the node's mempool before they are mined. It returns a hex filter ID; polling that ID with eth_getFilterChanges returns the hashes of pending transactions seen since your last poll. This lets you observe in-flight C-Chain activity — useful for mempool monitoring and fee tracking — though with Snowman finality landing in roughly one to two seconds, transactions move from pending to confirmed quickly. Create the filter at https://avalanche.therpc.io/YOUR_API_KEY.

Use cases

• Watch the C-Chain mempool for pending transactions and filter the resulting hashes down to a specific sender by inspecting each with eth_getTransactionByHash.
• Build an AVAX gas-price tracker by sampling the fees on pending transactions to gauge what tip is needed for fast inclusion.

Parameters

هذا الأسلوب لا يأخذ أي معاملات. مرر مصفوفة فارغة [].

Response

Example request

1curl https://avalanche.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H "Content-Type: application/json" \
4  -d '{
5    "jsonrpc": "2.0",
6    "method": "eth_newPendingTransactionFilter",
7    "params": [],
8    "id": 1
9  }'

Try it live in the Avalanche playground.

Errors & troubleshooting

Common pitfalls

• The filter yields only transaction hashes — fetch the full transaction details separately with eth_getTransactionByHash when you need sender, value, or calldata.
• A pending transaction may never be mined, may be dropped, or may be replaced by a higher-fee transaction with the same nonce; never treat a pending hash as confirmed AVAX activity.
• During C-Chain congestion the mempool can produce a large volume of hashes that floods each poll; for real-time consumption prefer eth_subscribe over a WebSocket connection rather than HTTP polling.

Supported networks

• Mainnet — Chain ID: 43114
• Fuji

See also

• eth_getFilterChanges
• eth_uninstallFilter
• eth_newFilter
• eth_subscribe

1curl https://avalanche.therpc.io/YOUR_API_KEY \
2  -X POST \
3  -H 'Content-Type: application/json' \
4  -d '{"jsonrpc":"2.0","id":1,"method":"eth_newPendingTransactionFilter","params":[]}'